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36 changes: 36 additions & 0 deletions Rotated_Sorted_Array.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
// Time Complexity :O(log n)
// Space Complexity :O(1)
// Did this code successfully run on Leetcode :yes
// Any problem you faced while coding this :no


//Check for target based on which side of the array is sorted.

class Solution {
public int search(int[] nums, int target) {
int low, mid, high;
low = 0;
high = nums.length - 1;

while (low <= high) {
mid = low + (high - low) / 2;
if (nums[mid] == target) { // found target in mid
return mid;
} else if ( nums[low] <= nums[mid]) { //left side is sorted
if (nums[low] <= target && target < nums[mid]) {
high = mid - 1;//target is in left side
} else {
low = mid + 1;//target is in right side
}
} else {//right side is sorted
if (nums[mid] < target && target <= nums[high]) {
low = mid + 1;//target is in right side
} else {
high = mid - 1;//target is in left side
}
}

}
return -1;//not found
}
}
35 changes: 35 additions & 0 deletions Search_2D_Matrix.java
Original file line number Diff line number Diff line change
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// Time Complexity :O(log mn)
// Space Complexity :O(1)
// Did this code successfully run on Leetcode :yes
// Any problem you faced while coding this :no


// Treat the matrix as flattened array and do binary search.
// Corresponding mapping: row = mid/n, column = mid%n

class Solution {
public boolean searchMatrix(int[][] matrix, int target) {
int m = matrix.length;
int n=matrix[0].length;
int low,mid,high;
low=0;
high = m*n-1;//last element

while(low<=high){
mid=low+(high-low)/2;
int row = mid/n;
int column = mid%n;
if(matrix[row][column] == target){
return true;//target found
}
else if(matrix[row][column] > target){
high = mid - 1;//search in left side
}
else{
low = mid + 1;//search in right side
}
}
return false;//not found

}
}
36 changes: 36 additions & 0 deletions Sorted_Array_Of_Unknown_Size.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
// Time Complexity :O(log n)
// Space Complexity :O(1)
// Did this code successfully run on Leetcode :no (premium question)
// Any problem you faced while coding this :no


// Increment low and high until reaching target range. Then do binary search in that range.

class Solution {

public int search(ArrayReader reader, int target) {
int low, mid, high;
low = 0;
high = 1;

while(reader.get(high) < target){ //increment low and high until we reach the range of target by doubling high
low = high ;
high = 2*high;
}

while(low <= high){
mid = low + (high - low)/2;
if(reader.get(mid) == target) { //found target in mid
return mid;
}
if(reader.get(mid) > target){ //search in left side
high = mid - 1;
}
else{//search in right side
low = mid + 1;
}
}

return -1;//not found
}
}